2 BULLETIN 358, U. S. DEPARTMENT OF AGRICULTURE. 



extent and trend of the variations may be determined and a more 

 definite knowledge of what to expect in the future may be obtained. 

 As every phase of the control of the weevil is based upon biological 

 facts, life-history studies have a very direct economic bearing upon 

 the boll-weevil problem. 



During 1913, 1914, and 1915 the writer conducted a number of 

 studies on the biology of the weevil at the Delta Boll Weevil Labo- 

 ratory at Tallulah, 1 La. The present' paper deals largely with the 

 results of these two years' observations, but before detailing these 

 it is probably best to review very briefly the times and conditions 

 under which the similar studies have been conducted. 



The earliest work was that at Victoria, Tex., in 1902 and 1903, 

 the results being published early in 1904. 2 This was followed by 

 similar investigations at the same place during 1904, and the results 

 of these studies were included in a bulletin issued in 1905. 3 



During 1910 similar investigations were conducted at Tallulah, 

 La., and the results were published in 191 1. 4 



Then, in 1912, these studies and such others as had been made 

 elsewhere were brought together in a large bulletin issued in 191 2. 5 



During 1913 another series of studies was conducted at Victoria, 

 Tex., to check those which had been made at the same place 10 

 years earlier. It was found that the weevils had made a number of 

 important changes in their life history, principal among these being 

 a much greater adaptability to plants other than cotton as food. 

 The biology of the Arizona Thurberia weevil was also studied, and 

 this variety was hybridized with the Texas cotton weevils. The 

 results of these studies are included in three papers. 6 



In 1914 the life history and habits of the Arizona weevil were 

 studied under natural conditions in the mountains near Tucson, 

 Ariz. These studies are discussed in two papers. 7 



i The writer wishes to acknowledge his indebtedness to Mr. E. K. Bynum for assistance in the work of 

 1915. 



a Hunter, W. D., and Hinds, W. E. The Mexican Cotton Boll Weevil. I*. S. Dept. Agr. Bur. Ent. 

 Bui. 45, 116 p., 16 pi., 6 fig., 1904. 



s Hunter, W. D., and Hinds, W. E. The Mexican Cotton Boll Weevil. TJ. S. Dopt. Agr. Bur. Ent. 

 Bui. 51, 1S1 p., 23 pi., 8 fig., 1905. 



* Cushman, R. A. Studies in the biology of the boll weevil in the Mississippi Delta region of Louisiana. 

 JwJour. Econ. Ent., v. 4, no. 5, 1911. p. 432-448. 



6 Hunter, W. D., and Pierce, W. D. Mexican Cotton Boll Weevil. U. S. Dept. Agr. Bur. Ent. Bui. 114, 

 188 p., 22 pi., 34 fig., 1912. 



e Coad, B. R., and Pierce, W. D. Studies of the Arizona Thurberia weevil on cotton in Texas. Proc. 

 Wash. Ent, Soc, v. 16, no. 1. p. 23-28. 1914. 



Coad, B. R. Feeding habits of the boll weevil on plants other than cotton. U. S. Dept. Agr. Jour. 

 Agr. Res., v. 2, no. 3, p. 235-245. 1914. 



Coad, B. R. Recent studies of the Mexican Cotton Boil Weevil. U. S. D^pt. Agr. Bui. 231,34 p., 1 fig. 

 1915. 



7 Coad, B. R. Relation of the Arizona Wild Cotton Weevil to Cotton Planting in the Arid West. U. S. 

 Dept. Agr. Bui. 233, 12 p., 4 pi. 1915. 



Coad, B. R. Studies on the Biology of the Arizona Wild Cotton Weevil. C~. S. Dept. Agr. Bui. 344, 

 23 p., 2 pi., 1 fig. 1916. 



